Numerous types of emulsifier or dispersant are known in the art and are used in many emulsion systems, such as, water-in-oil technology or oil-in-water technology, and these are disclosed in McCutcheon's Emulsifiers and Detergents, 1993, North American & International Edition and/or “Emulsions Theory and Practice,” written by P. Becher and published by Oxford University Press, 2001. A number of the dispersants that are known are derived from alk(en)yl succinic anhydrides or acids. However, due to the lipophilic nature of many dispersants derived from alk(en)yl succinic anhydrides or acids, it has been difficult to devise dispersants suitable for use in aqueous media-in-oil systems due to the lipophilic nature of the alk(en)yl.
International publication WO 03/029309 A2 discloses a hydrophilic emulsifier based on polyisobutylene for use in oil-in-water applications. The emulsifier is made up of (a) a lipophilic part that is derived from a polyisobutylene with a molecular weight between 300 and 10,000; (b) a hydrophilic part containing a polyethylene oxide chain; and (c) a linker derived from polybasic carboxylic acid such as maleic anhydride.
British Patent Application GB 2 017 719 discloses a blend of two types of alk(en)yl succinic polyester. The blend contains (i) a condensation product of a C8-18 alk(en)yl succinic anhydride with a polyalkylene glycol, and (ii) a condensation product of a C40-500 alk(en)yl succinic anhydride with a polyalkylene glycol.
British Patent Application GB 2 117 398 discloses surfactant compositions suitable for emulsification of methanol or ethanol in hydrocarbon fluids. The surfactant composition is a blend of two surfactants of (i) 10 to 90% of a block or graft copolymer derived from the residue of a monocarboxylic acid and another polymeric residue of a water-soluble polyalkylene glycol or polyalkylenoxy polyol; and (ii) 90 to 10% of a polyester obtained by the condensation of poly(isobutenyl) succinic acid or anhydride with a water-soluble poly(alkylene glycol).
U.S. Pat. No. 4,776,966 discloses a drilling fluid composition of an invert oil-based type emulsions that contains block or graft copolymers that are produced from polycarboxylic acids and a hydrophobic component derived from a mono-olefin and maleic anhydride. The maleic anhydride can be further reacted with compounds containing hydroxyl or amino groups, for example polyols or polyamines. However, the composition is only suitable for use in emulsions of brine-in-oil because it requires dissolved inorganic matter for emulsion stabilisation.
U.S. Pat. No. 7,045,580 discloses an amphiphilic compound containing: (a) a lipophilic component that is hydrocarbon group containing about 20 or more carbon atoms, (b) a hydrophilic component wherein the hydrophilic component is from (i) a monomer or an oligomer of an oxyalkylene group containing 2 or more carbon atoms; (ii) a monomer or an oligomer of an oxyalkylene group containing 3 or more carbon atoms; (iii) an oligiomer containing: (1) an oxyalkylene group containing 3 or more carbon atoms; (2) an oxyalkylene group containing 2 or more carbon atoms, provided component (2) is different from component (1); (iv) a hydrocarbyl substituted hydroxyamino group; (v) a polyhydric alcohol group; and (vi) a polyamino group; and (c) a linker covalently bonding the hydrophilic component and the lipophilic component, wherein the hydrophilic component is present in an amount sufficient to at least partially disperse the amphiphilic compound in water.
European Patent Application EP 0 156 572 A2 discloses surfactants derived from (a) a hydrophobic component and (b) a hydrophilic component covalently bonded together. The hydrophilic component further contains an anionic group selected from phosphates, phosphonates, sulphates, sulphonates and carboxymethyl. The hydrophobic component is derived from a polymer of a mono-olefin containing 2 to 6 carbon atoms typically has a molecular weight in the range 400 to 5000. The surfactants disclosed are useful in water-in-oil or oil-in-water emulsions and are incorporated into an oil phase. However, when the surfactants are used in oil-in-water emulsions, they tolerate being dispersed in water phases which are high in dissolved inorganic matter, for example, magnesium chloride or calcium chloride.
Further, in paint and coating technology, there is a further specific requirement to identify a dispersant capable of providing acceptable performance in aqueous media-in-solvent, particularly for universal tinter systems. Universal tinter systems are formulated in such a way that they are compatible and miscible with both water based paints and white spirit/aliphatic based paints. Conventional universal tinter systems may typically employ alkyl phenyl ethoxylates and glycols (a known volatile organic compound (VOC)). Due to environmental pressures, it would be desirable to formulate universal tinter systems with minimal to no alkyl phenyl ethoxylates and glycols. A particularly environmentally acceptable system would be waterbased (typically aqueous media-in-oil systems). Unfortunately, due to limited performance of known dispersants, universal tinter systems have not been optimised.
There is a need for a dispersant capable of providing acceptable performance in aqueous media-in-solvent (typically aqueous-in-oil). In particular, the dispersant may be suitable for universal tinter systems. The present invention provides a dispersant capable of providing suitable performance in aqueous-in-oil, including paint and coating technology.